H3C Technologies H3C S3100V2 Series Switches - Manual (Page 24)

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The switch removes the port from the outgoing port list of the entry in the forwarding table for that
multicast group when the aging timer expires.
IGMP snooping proxying
The IGMP snooping proxying function on an edge device reduces the number of IGMP reports and leave
messages sent to its upstream device. The device configured with IGMP snooping proxying is called
“IGMP snooping proxy.” It is a host from the perspective of its upstream device.
NOTE:
Even though an IGMP snooping proxy is a host from the perspective of its upstream device, the IGMP
membership report suppression mechanism for hosts does not take effect on it.
Figure 12 Network diagram for IGMP snooping proxying
As shown in Figure 12 , Switch A works as an IGMP snooping proxy. As a host from the perspective of the
querier Router A, Switch A represents its attached hosts to send membership reports and leave messages
to Router A.
Table 7 IGMP message processing on an IGMP snooping proxy
IGMP message Actions
General query
When receiving an IGMP general query, the proxy forwards it to all
ports but the receiving port. In addition, the proxy generates a report
according to the group memberships it maintains and sends the report
out all router ports.
Group-specific query
In response to the IGMP group-specific query for a certain multicast
group, the proxy sends the report to the group out all router ports if the
forwarding entry for the group still contains a member port.